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Serious air pollution, like this smog over China’s capital city, may increase the risk of obesity.

Air pollution is bad for our lungs. It may not be great for our waistlines either, a new study in rats finds.

China’s capital city of Beijing has some of the worst air pollution in the world. On really bad days, its air can host more than 10 times as many tiny pollutant particles as the World Health Organization says is safe for human health. In a new study, rats breathed in this air. And those rodents gained more weight, and were unhealthier overall, than were rats breathing much cleaner air. The results suggest that exposure to air pollution can raise the risk of becoming extremely overweight.

And, adds Loren Wold, “It is highly likely that this is happening in humans.”

Wold works at Ohio State University in Columbus. There, he studies how air pollution affects the heart. He was not involved in the new study. But he says it agrees with many other studies that have suggested air pollution can affect metabolism, which is how the body breaks down food and uses it for fuel.

Polluted air contains particles of ash, dust and other chemicals. Sometimes these particles are so numerous that they create a thick, dense smog can cuts visibility.

Earlier experiments among 18-year olds in Southern California had linked heavier traffic with higher body mass index (a measure of overweight and obesity). Areas with heavy traffic also tend to have more of those pollutant particles. Another study found that when pregnant mice were exposed to exhaust from diesel engines, their pups grew up to be heavier. The pups also developed more inflammation in their brains.

In the new study, researchers tested how Beijing’s polluted air affects the health of pregnant rats.

Jim Zhang is an environmental scientist at Duke University in Durham, N.C. He and his co-workers put rats in two indoor chambers in Beijing. They piped polluted air from the city directly into one chamber. Air piped into the other chamber went through a filter. That filter removed almost all of the big pollution particles from the air and about two-thirds of the smaller ones. This made the air more like what people breathe in typical U.S. cities and suburbs, Zhang says.

All rats ate the same type and amount of food. But after 19 days, the pregnant rats breathing the heavily polluted air weighed more than the rats breathing the filtered air. They also had higher amounts of cholesterol — a waxy, fatlike substance — in their blood than did the rats breathing filtered air.

Those breathing the dirtier air had higher levels of inflammation. This is a sign of the body responding to tissue damage. These rats also had higher insulin resistance. This means their bodies weren’t responding as well to insulin, a hormone that helps with using sugar for energy. Insulin resistance can lead to diabetes, a dangerous health condition.

Taken together, the scientists say, these symptoms indicate the rats were developing metabolic syndrome. It’s a condition that puts the animals at risk of heart disease and diabetes.

During the experiment, the pregnant rats gave birth. Their pups stayed in the chambers with their mothers. And young rats that breathed in the polluted air were heavier than pups born to moms living in the cleaner air. Like their moms, the pups breathing very polluted air had more inflammation and insulin resistance.

The longer these pups breathed the dirty air, Zhang says, the more unhealthy they became. This suggests that breathing polluted air for a long time can lead to sickness, Zhang says.

It’s not yet clear exactly how air pollution affects rat metabolism. But it seems, Zhang says, to impair how the animals process fat and sugar. Pollution also increases signs of inflammation in the lungs, blood and fat. Zhang says this is probably what led to weight gain in the animals.

Wold says it might be possible to create medicines that reverse the negative health effects of air pollution. But these medicines will take time to develop.

Until then, Zhang and Wold say that paying attention to air pollution levels can help people manage their health risks. On days when pollution levels are high, they recommend that people stay indoors, if possible — or at least avoid tough outdoor exercise .

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We’re safe for now. The way the universe is expanding, it won’t be tearing itself apart for at least a few billion years.

For those of you only now discovering that such an end was a possibility, here’s a little background. Observations of stars and galaxies indicate that the universe is expanding, and at an increasing rate. Assuming that acceleration stays constant, eventually the stars will die out, everything will drift apart, and the universe will cool into an eternal “heat death”.

But that’s not the only possibility. The acceleration is thought to be due to dark energy, mysterious stuff that permeates the entire universe. If the total amount of dark energy is increasing, the acceleration will also increase, eventually to the point where the very fabric of space-time tears itself apart and the cosmos pops out of existence.

One prediction puts this hypothetical “big rip” scenario 22 billion years in the future. But could it happen sooner? To find out, Diego Sáez-Gómez at the University of Lisbon, Portugal, and his colleagues modelled a variety of scenarios and used the latest expansion data to calculate a likely timeline. The data involved nearby galaxies, supernovae andripples in the density of matter known as baryon acoustic oscillations, all of which are used to measure dark energy.

The team found that the earliest a big rip can occur is at 1.2 times the current age of the universe, which works out to be around 2.8 billion years from now. “We’re safe,” says Sáez-Gómez.

Time equals infinity

And when is the latest it could happen? “The upper bound goes to infinity,” he says. That would mean the rip never comes and we end up with the heat death scenario instead.

Given that the sun isn’t expected to burn out for at least another 5 billion years, it would be surprising if the universe ended so early. But pondering our doom could be a worthwhile exercise anyway, Sáez-Gómez says. Scenarios like the big rip result from a lack of understanding of physics in particular our inability to marry quantum mechanics and general relativity, the theory of gravity. Exploring the possibilities could show us a way forward.

“You learn more about a physical theory by looking at the exotic and extreme cases,” says Robert Caldwell of Dartmouth College in New Hampshire, who helped come up with the big rip idea. He thinks Sáez-Gómez’s lower bound is very conservative, however – the universe is likely to last much longer. Even if it doesn’t, at least we’ve got a good run ahead of us. he says.

Neanderthal genes have been found in our genomes, on X chromosomes, and have been linked to traits such as skin colour, fertility and even depression and addiction. Now, an analysis of a Y chromosome from a 49,000-year-old male Neanderthal found in El Sidrón, Spain, suggests the chromosome has gone extinct seemingly without leaving any trace in modern humans.

This could simply be because it drifted out of the human gene pool or, as the new study suggests, it could be because genetic differences meant that hybrid offspring who had this chromosome were infertile – a genetic dead end.

Four gene mutations

Fernando Mendez of Stanford University, and his colleagues compared the Neanderthal Y chromosome with that of chimps, and ancient and modern humans.

They found mutations in four genes that could have prevented the passage of Y chromosome down the paternal line to the hybrid children.

“Some of these mutations could have played a role in the loss of Neanderthal Y chromosomes in human populations,” says Mendez.

For example, a mutation in one of the genes, KDM5D that plays a role in cancer suppression, has previously been linked to increased risk of miscarriages as it can elicit an immune response in pregnant mothers.

“That could be one reason why we don’t see Neanderthal Y chromosomes in modern human populations,” says Mark Pagel an evolutionary biologist at the University of Reading.

It could also be one factor keeping the two species as separate species.

The researchers also used the new DNA sequences to estimate the time when the most recent common ancestor of Neanderthal and modern human Y chromosomes existed. They came up with a figure of around 590,000 years ago, which agrees with other estimates for the split of the two groups.

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One of several antibiotic treatment options for the sexually transmitted disease gonorrhea seems to be losing its effectiveness, U.S. health officials warn in a new report.

The U.S. Centers for Disease Control and Prevention’s latest tracking suggests that although resistance to the antibiotic treatment cefixime went down between 2011 and 2013, it started to creep back up in 2014.

The good news is that cefixime isn’t usually the first drug of choice for treating gonorrhea infections. The CDC’s most recent guidelines for gonorrhea treatment (issued in 2012) recommend only using cefixime when the preferred option — ceftriaxone-based combination therapy — isn’t available. And the CDC’s new report doesn’t indicate any recent waning in the effectiveness of that combination therapy.

Still, indications of antibiotic resistance among any gonorrhea treatment is considered troubling, the study authors said.

“It is essential to continue monitoring antimicrobial susceptibility and track patterns of resistance among the antibiotics currently used to treat gonorrhea,” said study lead author Dr. Robert Kirkcaldy, an epidemiologist in the CDC’s division of STD prevention in Atlanta.

“Recent increases in cefixime resistance show our work is far from over,” he said.

The study findings are published as a research letter in the Nov. 3 issue of theJournal of the American Medical Association.

The CDC noted that gonorrhea is spread during unprotected vaginal, anal or oral sex. The sexually transmitted infection is particularly common among youth and young adults between the ages of 15 and 24.

Many people have no symptoms when infected. When symptoms do occur, they may include a painful or burning sensation when urinating; painful, swollen testicles and discolored discharge from the penis among men. In women, symptoms may include increased vaginal discharge and vaginal bleeding between periods. Rectal infections may spark soreness, itching, bleeding, discharge, and painful bowel movements, the CDC said.

If gonorrhea goes untreated, “serious health complications” can result, Kirkcaldy said. Those can include chronic pelvic pain, infertility and life-threatening ectopic pregnancy — an abnormal pregnancy that occurs outside of the uterus. In rare cases, gonorrhea can spread to your blood or joints, causing a potentially life-threatening infection, the CDC warned.

But when identified, antibiotics can provide an effective cure for those with gonorrhea.

The new CDC study looked at treatment outcomes among male gonorrhea patients who had been treated at public clinics across the United States between 2006 and 2014.

More than 51,000 samples were gathered across 34 cities. About one-third were collected in the western United States and one-third collected in the South. A little more than a quarter of the samples were drawn from men who either identified as gay or bisexual, the study said.

The investigators found that the CDC’s 2012 shift away from recommending cefixime and toward ceftriaxone-based combination therapy had a profound impact: while the combination therapy had been given to less than 9 percent of the patients in 2006, that figure shot up to nearly 97 percent by 2014.

Alongside that shift, the team found that cefixime-resistance went up from 0.1 percent in 2006 to 1.4 percent in 2011, and then back down to 0.4 percent in 2013. But by 2014 resistance trended upward to 0.8 percent, the research revealed.

What does this mean? “Trends of cefixime susceptibility have historically been a precursor to trends in ceftriaxone,” said Kirkcaldy. “So it’s important to continue monitoring cefixime to be able to anticipate what might happen with other drugs in the future.”

“The task force recommends screening for gonorrhea in sexually active women age 24 years or younger, and in older women who are at increased risk for infection,” she said.

The task force doesn’t advocate for or against screening for men, saying more research is needed to prove effectiveness. However, Kirkcaldy said that the “CDC recommends an annual gonorrhea screening for high-risk sexually active women and for sexually active gay, bisexual, and other men who have sex with men.”

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Naloxone, commonly known as Narcan, is a medicine that temporarily reverses the effects of opioid drugs such as heroin, morphine and oxycodone. If a person overdoses on an opioid, administering naloxone can help revive them.

Naloxone has been widely used in hospital emergency departments and many ambulance services since the 1970s. Ithas been shownto be remarkably safe, reliable and effective.

In most countries, including Australia, naloxone is only available in the community on prescription. But since the mid-1990s, clinicians and advocates have called for regulators to make naloxone more widely available to opioid users, their peers and family members who might be present or nearby when an overdose occurs.

It is likely that from February 2016 Australia will become the second country (after Italy in 1995), to have naloxone formally available without a prescription.

Prescription Take-Home Naloxone Programs

Take-home naloxone programs involving supply through prescription have successfully operated in Australia since April 2012, when a program was launched in the Australian Capital Territory. This was soon followed by programs in New South Wales, Western Australia, Victoria and South Australia.

Arecent evaluationfound that over two years, the ACT program reversed 57 overdoses. The program trained more than 200 participants (mostly opioid users) in overdose-prevention and management, and naloxone administration.

A 2010 survey of naloxone programs operating in the United States since 1996 found that 53,000 kits containing naloxone were distributed through 188 programs across 16 US states. This distributionwas reportedto have resulted in over 10,000 successful overdose reversals.

Growing international research on implementation of take-home naloxone programs provides further evidence that people who are at risk for overdose and other bystanders are willing and able to be trained to prevent overdoses and administer naloxone.

Recentresearch showsthat even very brief minimal training in using the medicine can be all that is needed to safely administer naloxone.

There is no evidence that wider availability of naloxone leads to riskier or more widespread drug use.

In 2014 the World Health Organizationrecommendedthat people likely to witness an overdose should have access to naloxone.

How Does Naloxone Reverse Overdoses?

When a person has an opioid overdose, they lose consciousness and their breathing can slow and even eventually stop. This results in damage to the brain and other organs and, eventually, death.

Most opioid overdoses occur among experienced users. People are most at risk of overdose when their opioid tolerance drops after a period of abstinence or reduced opioid use, such as after prison release, or if they use other drugs such as alcohol or sleeping pills in addition to the opioids.

Research showsthat most overdose deaths occur more than an hour after last injection and that others, such as friends or family, are usually nearby.

However, in most fatal cases, tragically, there is no intervention before death. This is primarily because most people are ill-equipped to respond to overdose (wrongly) assuming, for example, that the deep snoring or gurgling associated with impending respiratory collapse means that the person can be left to “sleep it off”.

But opioid overdose can be managed by monitoring the person, maintaining their airway, providing ventilation (with rescue breathing), basic life support and calling an ambulance.

Naloxone has a very specific action in reversing the effects of opioid intoxication. It does not produce any intoxication itself and has no effect on people who don’t have opioids in their system.

In an emergency situation, naloxone is typically administered by injection into a muscle. It can also be provided in a device so it can be sprayed into the nostrils, but naloxone is not licensed for nasal use in Australia.

Taking The Next Step

While over-the-counter access to naloxone will be an important step in facilitating wider access to the medicine, a number of measures will be needed to expand naloxone availability sufficiently to have a significant impact on the rate of lethal overdoses in the community.

Work will be done over the next few months to make the naloxone product packaging and instruction materials suitable for lay people buying it over-the-counter. Systems must also be developed to train people in how to use the medicine, such as through brief advice from pharmacy staff.

Naloxone is not a silver bullet for preventing overdose deaths. But its wider availability should be one important component of an effective strategy to prevent opioid overdose fatalities. The rescheduling of naloxone in Australia will set a new precedent for other countries and will help save lives for years into the future.